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Recent density functional theory studies of nonthermal pathways in Ge2Sb2Te5 (GST) have suggested that the strong bonding hierarchy of GST can be utilized to induce ultrafast and potentially more energy efficient transitions between structural phases [1]. In particular, the selective amplification of particular phonon modes that may lead to ultrafast transitions bypassing the thermodynamic phonon distribution opens a new frontier in materials science. To date, the vast majority of ultrafast pump-probe dynamical measurements have been purely optical leaving a great deal of uncertainty in the underlying structural changes and at the same time making it difficult to compare density functional theory based predictions to experiment. Recently optical pump/probe experiments by some of the current paper’s authors suggested that coherent phonons induced irreversible mode softening suggestive of an amorphous to crystalline transition in a superlattice of GeSbTe material at unusually low fluences. The need to investigate both structural changes and the underlying dynamics is thus of paramount interest.
The Japan Society of Applied Physics
Publication date: 
31 Aug 2013

Paul Fons, Kirill Mitrofanov, Alexander Vladimirovich Kolobov, Junji Tominaga, Alessandro Giussani, Karthick Perumal, Raffaella Calarco, Henning Richert, Roman Shayduk, Kotaro Makino, Muneaki Hase

Biblio References: 
Pages: 264-264
JSAP Annual Meetings Extended Abstracts The 74th JSAP Autumn Meeting 2013